Debugger dies when inspecting a recursive property

[Gnumaru]

Godot version

3.3.4 standard build for linux x64

System information

Ubuntu 21.04 x64

Issue description

The gdscript debugger dies when stopping on a breakpoint in a location where the inspector should draw a class property that contains a recursive value. Eg.: A reference to self.

Steps to reproduce

1. Create a new project
2. Create an empty scene
3. Attach a new script to the scene root node
4. Use the code bellow on the script and run the scene.

var a
func _ready():
    a = self
    breakpoint

Minimal reproduction project

No response

[Gnumaru]

I just noticed the same problem occur when creating a recursive meta property, even though neither the inspector tab nor the debugger tab draw the meta properties.

Using the code bellow yields the same result as the code above, that is, the debugger dies.

func _ready():
    get_script().set_meta('this', self)
    breakpoint

[sairam4123]

Can confirm, I was about to report it, related to #51049.

[akien-mga]

Can you reproduce it in 3.4?

[Gnumaru]

This:

var a
func _ready():
    a = self
    breakpoint

won't yield errors on 3.4. The debugger continues working normally.

But this:

func _ready():
    get_script().set_meta('this', self)
    breakpoint

altough won't kill the debugger, will make the console continuously spam the message:

ERROR: Condition "err" is true. Returned: err
   at: encode_variant (core/io/marshalls.cpp:1079)
ERROR: Condition "err" is true. Returned: err
   at: encode_variant (core/io/marshalls.cpp:1138)

The debugger won't die and you are still able to step through code, but since the console will be spamming the error messages, the editor performance degrades drastically.

[sairam4123]

It happens with this too.

func _ready():
	var d1 = {}
	var a1 = []
	d1["a"] = a1
	a1.push_back(d1)
	print(d1)
	breakpoint

Debugger dies in 3.4

lFC4Kv4iCg.mp4

[sairam4123]

Can confirm in 3.5.beta 7fcfde9. (Debugger crashes abruptly.)

[miscbill]

Similarly, in v4.1.1.stable.official [bd6af8e]

func _ready():
	set_meta("foo", self)
	breakpoint

leads to...

E 0:00:01:0832 Node2D.gd:4 @ _ready(): Potential infinite recursion detected. Bailing.
<C++ Error> Condition "p_depth > Variant::MAX_RECURSION_DEPTH" is true. Returning: ERR_OUT_OF_MEMORY
<C++ Source> core/io/marshalls.cpp:1118 @ encode_variant()
Node2D.gd:4 @ _ready()